Vegetation in different parts of the world
Natural vegetation is any tree or plant which grows naturally, without human intervention. It includes forests, grasslands and shrubs. A variety of vegetation can be found all over the world. We can classify the different vegetation on the basis of different geographical locations.
Coniferous Forests : Coniferous forests are made up mainly of cone-bearing or coniferous trees, such as spruces, hemlocks, pines and firs. The leaves of these trees are either small and needle-like or scale-like and most stay green all year around (evergreen). All are softwoods and are able to survive cold temperatures.
Coniferous forests are found mainly in the northern hemisphere. The northern coniferous forests are called taiga or boreal forests. They cover vast areas of North America from the Pacific to the Atlantic, and range across northern Europe, Scandinavia, Russia and across Asia through Siberia and Mongolia to northern China.
Coniferous trees grow well where summers are short and cool and winters long and harsh, with heavy snowfall that can last as long as 6 months. The needle-like leaves have a waxy outer coat which prevents water loss in freezing weather and the branches are soft and flexible and usually point downwards, so that snow slides off them. Coniferous trees
such as cypresses, cedars and redwoods are found in warmer regions.
Cypresses, cedars and redwoods grow upright, the tallest of them can
reach 20m in height. The trees are usually pyramid-shaped. Mosses,
liverworts and lichens are also found on the forest floor and grow on
tree trunks and branches.
Trees in the Temperate Forest: The temperate forests are of two types. The temperate deciduous forest and temperate evergreen forest.
The Temperate deciduous forest- The deciduous forest has four distinct seasons, spring, summer, autumn, and winter. In the autumn the leaves change color and begin to fall. During the winter months the trees lose all their leaves and are bare. The word "deciduous" means exactly what the leaves on these trees do: change color in autumn and fall and grow back again in the spring. This adaptation helps trees in the forest survive the severe winter. The temperate deciduous forest occupies most of the eastern part of the United States. The dominant plant species of this region are broad-leaved deciduous trees. Oak, hemlock, maple etc.
Deciduous trees in autumn Deciduous trees in summer
Temperate Evergreen forest:Temperate evergreen forests are characterized by their hardy trees. Trees need to withstand sandy, rocky, and basically poor quality soil, occasional fires, droughts and cold weather. These forests are generally dominated by pine trees, but also support many other kinds of vegetation like eucalyptus, pine, fir, spruce, and cypress. Broad-leaf evergreens dominate forests in eastern Asia, coastal regions of New Zealand and Australia, and parts of Chile.
Grasslands: Grasslands are large, rolling terrains of grass. Latitude, soil and local climates for the most part determine what kinds of plants grow in a particular grassland. Mostly tall grass is the only vegetation seen here with very few shrubs and trees. The climate is extreme with cold winter and hot and dry summers. Droughts and fire are common here. Forest fires prevent trees from flourishing here.
Grasslands are known by different names in different places.
Savannas in Africa
Prairies in North America
Steppes In North Asia and Russia
Pampas in South America.
Veld in South Africa
Downs In Australia
Tropical Rainforest trees-
Almost all rain forests lie near the equator. They have warm and wet climate, with plenty of rainfall. More than two thirds of the world's plant species are found in the tropical rainforests. Plants provide shelter and food for rainforest animals as well as provide much of the world's oxygen supply. The warm and humid climate provides an ideal environment for many species of insects, birds and animals. Rainforest trees are quite different from trees of the temperate forests. In the rainforest, trees grow to gigantic size, supported by strong, buttress root. Huge creepers twine themselves around the trunks of trees.
Many varieties of food and other useful things are obtained from these forest. We can find the ebony, mahogany ,cocoa, banana , bamboo, rubber tree, cassava , avocado trees, palms etc here. About 1/4 of all the medicines we use come from rainforest plants. The Amazon rainforest in South America is the largest tropical rainforest in the world, covering over five and a half a million square kilometers.
Rainforests have four very distinct layers of trees.
Emergent: Giant trees that are much higher than the average canopy height. It houses many birds and insects.
Canopy: The upper parts of the trees. This leafy environment is full of life in a tropical rainforests and includes birds, reptiles, mammals, and more.
Understory: A dark, cool environment under the leaves but over the ground.
Forests Floor: Teeming with animal life, especially insects, the largest animals in the rainforests generally live here.
Desert plants Thorny shrubs and cactus are found in the deserts. Only plants that can survive the extreme heat are found here. The cactus has fleshy stems which stores water. It does not have leaves instead its leaves are modified into spines. Date palms and Acacia are also commonly found in the desert. The desert plants are adapted to survive with very less water as there is hardly any rainfall in these regions. These plants have long roots which go deep in search of water. Due to the extremely harsh weather, very few plants and trees are found in this region.
Mangroves - Mangroves are a group of trees and shrubs that grow near sea coasts or river deltas. There are about 80 different species of mangrove trees. All of these trees grow in areas with low-oxygen soil, where slow-moving waters allow fine sediments to accumulate. Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures. Mangroves are very useful in controlling soil erosion near the coasts. These trees have roots that appear to be hanging which are also called breathing roots. These portions of the roots come out of the soil above the water level and take oxygen from the air.
Exercises
Fill in the blanks.
(cactus, humid, needle-shaped, broad, rainforest, mangroves)
1. Trees in the coniferous forest have______leaves.
2. Deciduous trees have ______leaves.
3. The rainforest have a warm and ______climate.
4. The ______is a thorny plant found in the desert.
5. ______are plants found on marshy land near sea coasts or river banks.
6. Most of the world’s animal and plant species live in the ______.
Choose the correct option.
1. Plants in the desert have ______roots.( small/long)
2. Deciduous trees shed their leaves in ______(spring/autumn)
3. The ______is the largest rainforest in the world.(Amazon/Congo)
4. The ______are very useful in controlling soil erosion near the coasts. (pine trees/mangroves)
5. The ______have an extreme climate , with harsh summers and very cold winters.(grasslands/rainforests)
Complete the table.
Name of the forest / Plants found in the forest / Adaptation of these plantsConiferous forest
Temperate Deciduous Forest
Temperate Evergreen forest
Deserts
Rainforest
Mangrove forests
Grasslands
Think and answer.
1. The Rainforests receives the maximum amount of rainfall. Justify the statement.
2. How do the trees in the deciduous forest adapt to the severe cold winter?
3. The mangroves are known as plants with breathing roots. Why?
Research and find out:
1. The rainforest of Africa is known as ______
2. Some animals found in the coniferous forest are______
3. Some animals found near mangroves swamps are______
4. The desert in Africa is known as ______
5. The animals found in the Prairies of North America.______
6. A cold desert .______
Deforestation and its effects on communities dependent on forests for livelihood.
We humans are the only living things that can alter the environment to suit our needs. Our activities have upset the balance in nature and put the survival of all living things in danger. As our population grows, we need more land to make houses, to produce food and set up factories to satisfy the needs of the growing population. We get this land by cutting down forests. This is known as deforestation. It refers to the cutting of trees in forested areas.
Deforestation
On one hand people cut down trees that give us oxygen, to satisfy our various needs like fuel, furniture and building material. On the other hand, burning fuels and pollution from factories are adding to increase in carbon dioxide in the atmosphere. This has affected the balance in nature.
Forests act like the planet’s air conditioning system and help to cool the environment. Trees absorb the impure carbon dioxide from the air and give out fresh oxygen . Due to deforestation the level of carbon dioxide in the atmosphere has increased as we have fewer trees to purify it. This has made our planet much hotter that what it used to be. This is leading to Global Warming. Forests are also responsible for keeping the atmosphere cooler and bringing rainfall. Without forests the atmosphere will become a dry place without rainfall.
Deforestation also leads to soil erosion. The removal of top soil by water, wind or ice is known as erosion. Plant roots firmly bind the soil. In the absence of plants, soil becomes loose. So it can be moved by wind and flowing water. Erosion of soil is more severe in areas of little or no surface vegetation. The loose soil will become barren and unfertile, and thus unfit for cultivation. It is also called desertification of soil.
Effect of deforestation on the people dependent on forests.
A small population of people lives in forests. In India they consists of tribal people. They depend on the forest for their living. They practice agriculture, gather honey, gum, resins, wood, fruits, medicinal herbs etc. They also make handicrafts from sandalwood, bamboo and rosewood trees. They have a good knowledge of medicinal plants and sell medicinal herbs. The cutting down of forests has seriously affected these tribes. They have to leave their land and migrate to other places in search of work.
Birds and animals lose their natural habitat due to cutting down of forests. Thus many species face extinction.
Various movements to protect to protect forests across the world.
In order to maintain proper ecological balance a certain percentage of the total land area of any country should have forest cover. If this is reduced it results in both floods and famine. In Afforestation programmes forest trees are planted in areas where forests were destroyed and also on waste land. Afforestation is the re-growing of forest areas by planting trees. Realizing the importance of trees and forests , Afforestation is being done by both government and private organizations.
Government have recognized many forest areas as reserved forest and are protected by forest official. Cutting trees and hunting animals in these areas have been banned and is a punishable offence.
Van Mahotsav- This is an annual tree-planting festival in India, celebrated in the first week of July., wherein new saplings are planted. On this day adults and children plant new saplings.
Chipko Movement- This movement started in a village
in Uttar Pradesh. The villagers led by Sundarlal Bahuguna
and others resisted the cutting down of trees. When the
wood cutters tried to cut the trees, people put the hands
around the trees and prevented them from cutting it.
This was called the Chipko Movement which became
very popular and spread to the other parts of the country.
Exercises:
Fill in the blanks.
(soil erosion, pollution, deforestation, afforestation, roots, forest resources)
1. Cutting down trees in forested areas is known as ______
2. ______from factories and burning fuels increase carbon dioxide in the atmosphere.
3. The removal of the top soil by water, wind or ice is known as ______.
4. ______of the trees hold the soil firmly in place.
5. Tribes living in the forest depend on the ______for their living.
6. Planting and re-growing trees in wasteland is known as ______
Write true or false.
1. The Tribes in the forest are responsible for deforestation.______
2. Due to deforestation many animals face extinction.______
3. In India cutting trees in reserved areas is illegal.______
4. Soil erosion leads to desertification of the land.______
5. Van Mahotsav is a festival which supports Afforestation.______
6. Deforestation has no impact on the climate of a place.______
Match the following.
1 / Chipko movement / A / Reserved forest area2 / Tribes / B / Removal of topsoil
3 / Wild life sanctuary / C / Increase in carbon dioxide
4 / Global warming / D / Sundarlal Bahuguna
5 / Soil erosion / E / Knowledge of medicinal herbs
1 / 2 / 3 / 4 / 5
Answer the following:
1. What do the tribes do for a living?
2. How is deforestation responsible for soil erosion?
3. What are the effects of soil erosion and what measures can we take to control it?
4. Trees are responsible for bringing about rainfall. Explain.
Natural calamities
Our Earth is an ever-changing dynamic planet. Different forces of nature cause various changes in the atmosphere, crust or interior of the Earth. Sometimes these changes result in large scale damage to life and property. When they are caused by natural factors we call them natural calamities. A natural calamity is an adverse event resulting from natural processes of the Earth; example include floods, severe weather,volcanic eruptions, earthquakes, tsunamis and other geologic processes.